A voltage reference is an essential building block in analog and mixed-signal Integrated Circuits (ICs), including voltage regulators (for example, Low-Dropout (LDO) voltage regulators and regular voltage regulators), DC-DC converters, data converters, etc. A voltage reference ideally serves to generate an uninterrupted reference voltage that is insensitive to process, supply voltage and temperature (PVT).
Moreover, a voltage reference that is used for space applications should also be insensitive to radiation because the operating environment can be harsh in space. Some of the primary radiation effects that may happen in space include Total Ionizing Dose (TID), Single Event Transient (SET), Single Event Upset (SEU) and Single Event Latchup (SEL). Among these radiation effects, SEL is the most critical effect because it often results in permanent damage to ICs.
Conventionally, parasitic bipolor junction transistors (BJTs) have been used in to provide voltage references. However, such conventional techniques provide ICs that are highly susceptible to SEL. Furthermore, a voltage reference that is obtained using the BJTs manifest as a separate IC, and cannot be integrated with other ICs. This means that such voltage references are inappropriate for a System-on-Chip (SOC) realization. FIG. 1 shows a DC-DC convertor that is obtained by Radiation Hardening By Process (RHBP). This application uses the conventional BJT-based rad-hard voltage reference and manifests as a separate IC from the DC-DC converter.
A need therefore exists to provide a method that provides a voltage reference in a circuit that is independent of temperature and power supply variation. It is against this background that the present invention has been developed.